Natural intraepithelial lymphocyte populations rise during necrotic enteritis in chickens

Intraepithelial lymphocytes (IEL) reside in the epithelium at the interface between the contents of the intestinal lumen and the sterile environment of the lamina propria. Because of this strategic location, IEL play a crucial role in various immunological processes, ranging from pathogen control to tissue stability. In mice and humans, IEL exhibit high diversity, categorized into induced IEL (conventional CD4 and CD8αβ T cells) and natural IEL (TCRαβCD8αα, TCRγδ, and TCRneg IEL). In chickens, however, the subpopulations of IEL and their functions in enteric diseases remain unclear. Thus, we conducted this study to investigate the role of IEL populations during necrotic enteritis (NE) in chickens. At 14 days of age, sixty-three Specific-pathogen-free (SPF) birds were randomly assigned to three treatments: Control (sham challenge), Eimeria maxima challenge (EM), and Eimeria maxima + Clostridium Perfringens (C. Perfringens) co-challenge (EM/CP). The EM and EM/CP birds were infected with Eimeria maxima at day 14 of age, and EM/CP birds were additionally orally inoculated with C. perfringens at days 18 and 19 of age. Birds were weighed at days 18, 20, and 26 of age to assess body weight gain (BWG). At 20 days of age (1 day-post C. perfringens infection; dpi), and 26 days of age (7 dpi), 7 birds per treatment were euthanized, and jejunum was harvested for gross lesion scores, IEL isolation, and gene expression. The EM/CP birds exhibited subclinical NE disease, lower BWG and shorter colon length. The Most changes in the IEL populations were observed at 1 dpi. The EM/CP group showed substantial increases in the total number of natural IEL subsets, including TCRαβ+CD4-CD8-, TCRαβ+CD8αα+, TCRγδ+, TCRneg and innate CD8α (iCD8α) cells by at least two-fold. However, by 7 dpi, only the number of TCRαβ+CD4-CD8- and TCRαβ+CD8αα+ IEL maintained their increase in the EM/CP group. The EM/CP group had significantly higher expression of proinflammatory cytokines (IL-1β and IFN-γ) and Osteopontin (OPN) in the jejunum at 1 dpi. These findings suggest that natural IEL with innate and innate-like functions might play a critical role in the host response during subclinical NE, potentially conferring protection against C. perfringens infection.

A two-generational reproductive study to assess the effects of Juglans regia on reproductive developments in the male and female rats

Environmental pollutants and lifestyle severely threaten human and animal health, leading to disturbances of various functions, including infertility. So, exploring a safe treatment that could effectively reverse infertility remains a challenge. The current study was intended to explore the fertility-enhancing effect of Juglans Regia oil in two successive generations of rats; F0 and F1. J. Regia oil was initially tested for in vitro antioxidant assay via ROS and DPPH, followed by in vivo toxicity testing. In the fertility assessment, eighteen pairs of male and female rats (n=36, 1:1, F0 generation) were divided into three groups and dosed with 1 mL/kg and 2 mL/kg daily of J. Regia oil and saline, respectively, up to pre-cohabitation, cohabitation, gestation and lactation periods. The reproductive performance, including body weight, live birth index, fertility index, and litter size, was assessed. Hormonal and antioxidant markers of F1 generations were assessed with the histopathological evaluation of male and female organs. The oil of J. Regia showed great antioxidant potential (P < 0.05) in DPPH (1,1-diphenyl-2-picrylhydrazyl) and ROS (Reactive Oxygen Species) methods (P<0.05). The continued exposure of the F0 and F1 generations to J. Regia oil did not affect body weight, fertility index, litter size, and survival index. We have found pronounced fertility outcomes in both genders of F0 and F1 generations with J. Regia 2 mL/kg/day in comparison to the control. Results showed that J. Regia significantly increased (P < 0.05) luteinizing hormone (LH), plasma testosterone, follicular stimulating hormone (FSH), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in both generations. Histology of both generations reveals improved spermatogenesis and folliculogenesis with enhanced architecture. Altogether, the present results suggest that J. Regia improved fertility in both male and female rats by improving hormonal activities and oxidative stress.

Workplace oral health promotion activities among community-aged care workers: A qualitative exploration

BACKGROUND

The workplace is an ideal-and priority-setting for health promotion activities. Developing and implementing workplace health promotion interventions, including oral health promotion activities, can help create health-supporting workplace environments.

OBJECTIVE

To pilot workplace oral health promotion activities among staff working in the aged care sector, report their impact and explore participants' views on the factors that contribute to participation and effectiveness.

METHODS

This study comprised three phases: (i) the development and face validation of the resources, (ii) a 3-h educational session and (iii) five interview sessions with participants 4-6 weeks following the education session. The recorded interviews were transcribed verbatim and analysed thematically.

RESULTS

Eleven community-aged care workforce were invited to five feedback sessions. Ten participants were female and ranged in age from 18 to 64. All participants gave favourable comments about the content and delivery of the training session and accompanying resources. The participants felt that the benefits of WOHP include improved staff knowledge, awareness and oral care routine, the ability to share (and put into practice) the gained knowledge and information with their dependants, a lower risk of having poor oral health that adversely affects their well-being and work tasks, and potentially beneficial impacts on the organization's staff roster. Their attendance in the WOHP was facilitated by being paid to attend and scheduling the sessions during work time. Future WOHP suggestions include the possibility of a one-stop dental check-up at the workplace or staff dental care discounts from local dental practitioners and combining oral health with other health promotion activities.

CONCLUSIONS

Planning and implementing WOHP was deemed acceptable and feasible in this study context and successfully achieved short-term impacts among community-aged care workers. Appropriate times and locations, organizational arrangements and a variety of delivery options contributed to successful programme planning and implementation.

Ultra-sculpturing of seed morphotypes in selected species of genus Salvia L. and their taxonomic significance

The taxonomic importance of macromorphological and micromorphological seed characteristics was investigated using SEM of ten species of the Salvia genus from Pakistan. The aim was to identify diagnostic seed ultrastructural features that could aid in species delimitation, correct identification and phylogenetic position. The ultrastructure of Salvia varies greatly, and a wide range of unique micromorphological features have been observed. Seed micromorphological features were explored by SEM, including seed shape, colour, texture, cell outline, surface sculpturing, epidermal cell arrangement, anticlinal, and periclinal wall pattern. Seed shapes were categorized as obovate, spherical, spheroid, broadly elliptic, elliptic and oblong, mostly with a terminal hilum. Seed colours were black, light brown, dark brown, brown and yellow. Exo-morphological characters, i.e. epidermal cell arrangements, included irregular, wavy pentagonal-hexagonal, regular pentagonal-hexagonal. Cluster analysis was used to assess similar and distinct species within Salvia with a feasible explanation. Taxonomic keys were made based on micromorphological qualitative features that help to delimit species and identify them quickly within the Salvia genus. Seed morphology of ten Salvia species was described and investigated, and the diagnostic significance of features evaluated using SEM. This study analysed seed features, especially at the species level, which might provide much new taxonomic information. The results revealed that, in seed morphology, using SEM can help with taxon identification, especially at the genus and species levels.

Effect of Agaricus blazei Murill on exploratory behavior of mice-model

Increased anxiety and depressive symptoms have reported to be its association with long term illness. Because of having unwanted effects of newly available drugs, patients administering anxiolytic drugs usually discontinue the treatment before they are completely recovered. Therefore, there is a serious need to develop new anxiolytic drugs. The anxiolytic effect of hydro-alcoholic extract of Agaricus blazei in animal models was assessed. 24 male mice (Mus musculus genus) were included in the study. Four groups were prepared and each group contained six animals. The groups were vehicle control, positive control (diazepam 1.0 mg/kg, i.p.) as well as two treatment groups receiving Agaricus blazei hydro-alcoholic extract at a dose of 136.50 mg/kg and 273.0 mg/kg orally. The Marble burying test, Nestlet shredding test and Light and Dark box test used to assess anxiolytic activity. Mice administered with diazepam 1.0 mg/kg, i.p. while hydro-alcoholic extract of AbM (136.50 and 273.0 mg/kg, respectively) was administered via oral route which exhibited marked reduction in number of marbles-burying as compared to vehicle control group. Mice administered with diazepam 1.0 mg/kg, i.p. and Oral administration of hydro-alcoholic extract of AbM (136.50 and 273.0 mg/kg, respectively) exhibited significant decrease in nestlet shredding in comparison to vehicle control group. The oral administration of hydro-alcoholic extract at a dose of 136.5mg/kg and 273mg/kg showed elevation in time spent in light box and was comparable to standard treated group while time spent by mice following oral administration of hydro-alcoholic extract of Agaricus blazei at a dose of 273.0 mg/kg also showed elevation and was found to be more near to standard treated group (diazepam 1 mg/kg, i.p.).

Prevalence of cutaneous leishmaniasis in the largest populated city Karachi, Pakistan

The study was undertaken from September 2018 to April 2019 to determine the prevalence of cutaneous leishmaniasis in human beings living in six districts of Karachi. Suspected persons were screened for the disease and positive cases were identified on the basis of skin lesions and blood samples. Samples were observed by mounting their smear. A total of 207 subjects of different ages and sex groups were investigated, however, only 192 (92%) of the suspected cases were found to have the disease 64% of cases were male which were significantly high (p 0.05), than female 36%. The lesion was more frequently detected among the youth ages of 21-30 years (31%) as compared to other groups. In both sexes, legs were found to be more infected (25% male + 20% female) followed by arms (20% male + 0% female) and face (15% male +11% female). The mixed body parts had shown the lowest infections such as (4% in males + 5%) in females. In conclusion, the highest and lowest leishmaniasis infections were observed in District West (23% male + 9% female) followed by District East (15% male + 7% female), District Malir (11% male+ 4% female), District Central (7% male + 5% female), District Korangi (4% male + 7% female) and District South (4% male + 4% female) respectively.

Differing commissioning arrangements may contribute to geographic variation in clinical management of digital ulcers in systemic sclerosis

Phosphodiesterase inhibitors (such as sildenafil) and endothelin receptor antagonist, bosentan, are effective for digital ulcer disease in systemic sclerosis (SSc-DU) and are endorsed in international treatment recommendations. Commissioning of high-cost drugs, such as bosentan, however, differs across devolved nations of the UK. We report a multicentre service evaluation project to examine 'real world' management of SSc-DU before and following the 2015 UK Scleroderma Study Group (UKSSG) guidance, across south-west (SW) England and Wales. Results showed that iloprost and sildenafil use for SSc-DU was higher in patients in Wales prior to 2015. Between 2015-2017, sildenafil use for SSc-DU increased in SW England while remaining stable in Wales. Bosentan use for SSc-DU after 2015 in SW England increased, while remaining stable and proportionately lower in Wales. These findings demonstrate that differing commissioning guidance across devolved nations of the UK seems to contribute to geographic variation in patient care.

Limestone particle size, calcium and phosphorus levels, and phytase effects on live performance and nutrients digestibility of broilers

Limestone particle size (PS) affects its solubility and thus can influence broiler performance by altering the rate of calcium (Ca) release into the gastrointestinal tract. The objective of this research was to determine, using 2 × 2 × 2 factorial arrangement, the influence of PS (fine and coarse) and supplemented phytase (0 and 1,000 FYT/kg) in diets formulated with 2 Ca and P_i levels (positive control [PC]; negative control [NC]) on live performance, bone ash, and apparent ileal nutrients digestibility (AID). Starter PC: 0.9 Ca and 0.45 Pi; NC: 0.72 Ca and 0.03 Pi. Grower PC: 0.76 Ca and 0.38 Pi; NC: 0.58 Ca and 0.23 Pi. The 8 diets were assigned randomly to a total of 1,512 birds, with 21 birds per pen and 9 pens per treatment. The main effects of PS and Ca and P_i levels had no influence on feed intake (FI), body weight gain (BWG), or feed conversion ratio. Adding phytase improved BWG by 8 g and 50 g and FI by 25 g and 56 g at 0–14 D (P ≤ 0.05) and 0–35 D (P ≤ 0.05), respectively. Interaction between Ca and P_i levels and phytase improved BWG and FI for 0–14 D (P ≤ 0.05) and BWG during 15–28 D (P ≤ 0.05) for PC without phytase and for PC and NC with phytase when compared with NC without phytase. Birds fed PC without phytase, or either PC or NC with phytase were about 96 g heavier than NC without phytase. Birds fed either PC or NC diet with coarse limestone or PC with fine limestone gained approximately 14 g more (P ≤ 0.05) than birds fed NC with fine limestone for BWG at 0–14 D (P ≤ 0.05). Phytase increased tibia bone ash (14 D) by 1% (P ≤ 0.05). AID of Ca and P_i at 14 D was improved (P ≤ 0.05) by 66% when phytase was added to coarse limestone. Results indicate that phytase improved broiler performance without being affected by PS. Furthermore, phytase had greater influence on coarse limestone than on fine limestone for bone ash and AID. Ca and P_i levels were the most influential factors in determining bone ash although phytase inclusion could lead to an improvement during early days.

Impacts of improved extension services on awareness, knowledge, adoption rates and perceived benefits of smallholder dairy farmers in Pakistan

The provision of effective extension services to smallholder farmers across both developing and developed countries remains a challenge worldwide. The objective of the study is to demonstrate the impacts of improved extension services on awareness, knowledge, adoption rates and perceived benefits of smallholder dairy farmers in Pakistan. An extension program was developed and implemented in five districts of Punjab (Okara, Pakpattan, Jhelum, Kasur and Bhakkar) and two districts of Sindh (Thatta and Badin) provinces. The extension program involved the provision of research-based information on a monthly basis to smallholder farming families (FF = 523) over a 4-year period. The extension program was primarily a knowledge transfer-based system, but also relied on farmer engagement and feedback to help drive research and topics for discussion. No financial incentives were provided to the farmers for their participation. A ‘whole-family approach’ was used in the extension program, where comprehensive interdisciplinary training on the whole dairy-farming system was provided to the males, females and children of the farming household. To encourage greater participation and support different learning strategies, several information transfer media were used (including group discussions, one-on-one visits, practical demonstrations, problem-based learning techniques and videos). To assess the impact of this extension program on farms involved, data on farmer awareness, knowledge, adoption and their perceived benefits were collected using a mixed-method approach from three different groups of farmers; registered (IMPreg = 179) farmers directly involved in the extension program, non-registered (IMPnon-reg = 116) farmers indirectly benefiting from the program and traditional (IMPtrad = 104) farmers not associated with any project activities. Overall awareness, knowledge and adoption rates relating to seven different recommendations in the extension program were significantly (P &lt; 0.05) higher in the registered farmers than in the non-registered and traditional farmers. The perceived benefits of the adopted recommendations varied between the different extension messages, but farmers described that they observed increases in milk production, improvements in animal health (body condition and morbidity) and labour efficiency (time savings). These results suggest that adopting improved extension services using a whole-family approach we can significantly achieve higher adoption rates, leading to on-farm benefits to smallholder dairy farmers and their families.

Unusual presentation of eosinophilic fasciitis (EF) with a raised ALT

Eosinophilic fasciitis (EF) is a syndrome of unknown aetiology characterised by progressive collagenous thickening of the subcutaneous fascia. Limb oedema can precede the skin thickening and induration classically associated with EF. We describe a case of EF in a 31-year-old woman who presented to her general practitioner with lower limb oedema and stiffness. Blood tests in primary care showed a persistently raised alanine transferase (ALT). No hepatic cause for her raised ALT was found despite investigation. The unusual manner of her presentation led to delay in her referral to the autoimmune connective tissue disease (CTD) clinic. This case illustrates the importance of considering autoimmune CTD such as EF in young patients presenting with limb oedema and raised ALT, as early treatment influences prognosis and functional recovery.

Lesson of the month 2: Dry skin, yellow nails and breathlessness

Interstitial lung disease (ILD) is a common clinical problem, representing a group of diseases consisting of inflammation and progressive fibrosis of the lung. In some cases, an underlying cause is not identified; however, a significant proportion of ILD is associated with connective tissue disease (CTD). A detailed history and examination is the most important part of the assessment of patients with suspected ILD and will direct further investigation. This case illustrates the importance of identifying the symptoms and signs of CTD when assessing a patient with ILD. In addition, we describe an unusual presenting manifestation of yellow nails, which is not a recognised feature of CTD-ILD, but improved following immunomodulatory treatment for the overall condition.

Title: role of matrix metalloproteinase -9 in progression of tuberculous meningitis: a pilot study in patients at different stages of the disease

BACKGROUND

TBM (Tuberculous meningitis) is severe form of tuberculosis causing death of one third of the affected individuals or leaving two-third of the survivors disabled. MMP-9 (Matrix metalloproteinase-9) is produced by the central nervous system in a variety of inflammatory conditions and has a role in the breakdown of extracellular matrix and blood-brain barrier.

METHODS

In this study, the levels of MMP-9 and its inhibitor, TIMP-1 (tissue inhibitor of metalloproteinases-1), were screened using zymography and reverse zymography in cerebrospinal fluid and serum of tuberculous meningitis patients at different stages of the disease. Further, role of MMP-9 as therapeutic target was studied in C6 glioma cells infected with Mycobacterium tuberculosis H₃₇R_v. Cells were treated with dexamethasone or SB-3CT (specific inhibitor of MMP-9) in combination with conventional antitubercular drugs.

RESULTS

MMP-9 levels in patients were increased as the disease progressed to advanced stages. The infection led to increased MMP-9 levels in C6 glioma cells and specific inhibition of MMP-9 by SB-3CT augmented bacillary clearance when used along with antitubercular drugs.

CONCLUSION

MMP-9 plays a prominent role in progression of tuberculous meningitis from initial to advanced stages. Increased levels of MMP-9 during advancement of the disease leads to degeneration of nervous tissue and blood brain barrier disruption. Hence, MMP-9 can be considered as a therapeutic target for efficient management of TBM and can be explored to inhibit further progression of the disease if used at an early stage.

Molecular basis for odorant receptor tuning: a short C-terminal sequence is necessary and sufficient for selectivity of mosquito Or8

A birth-and-death evolutionary model for odorant receptor gene repertoires presumes the creation of repertoires with the capacity for high-level diversity and rapid ligand specificity change. This changes the recognised odour space, directly affecting fitness-related behaviours and ultimately affecting adaptation to new environments and resources. The proximate molecular mechanisms underlying the tuning of odorant receptor repertoires, and thus peripheral olfaction, are unclear. In the present study, we report a concrete example of this model of odorant receptor evolution leading to rapid changes in receptor tuning that leave the peripheral neuronal circuitry intact. We identified a conserved odorant receptor gene in mosquitoes, Or8, which in Culex quinquefasciatus underwent a duplication and inversion event. The paralogues differ in only minor structural changes manifesting at the C-terminus. We assessed the specificity of the paralogous odorant receptors and receptor neurones. We found that the functional tuning of the receptor was indeed reflected in minor differences in amino acid structure. Specifically, we found that enantiomeric specificity of these mosquito Or8 paralogues relies on eight C-terminal amino acids encoded in the final exon of the gene; thus, the birth of a paralogous odorant receptor can change the tuning of the peripheral olfactory system.

Socio-demographic features and knowledge of diabetes mellitus among diabetic patients in kuwait

OBJECTIVE

To determine the socio-demographic profile and assess knowledge about the nature, symptoms, complications, and treatment of diabetes mellitus among diabetic patients in Kuwait.

METHODS AND RESULTS

A cross-sectional sample survey of 788 patients attending specialized diabetic clinics was conducted in 1995. Kuwaitis were significantly more represented in this sample than in the general population (52.5% versus 37%). Female to male ratio among Kuwait population was 1.07 and among non-Kuwaitis it was 0.28. Age at diagnosis ranged between sixteen to eighty years with a mean of 48 ± 10.8 years. Overall knowledge was assessed by percentage of correct responses for individual knowledge questions. There was no significant difference in knowledge of diabetes seen among Kuwaitis (66%) and non-Kuwaitis (64%). No sex difference in knowledge was seen. Knowledge about diabetes was highest among diabetic patients with increasing educational achievement but lowest with advantage age.

CONCLUSION

Most patients lack a lot of information that could have a significant impact on their motivation and ability to remain healthy. To overcome this growing problem, instructing a standard diabetes education system was found to be one way of improving in morbidity due to diabetes and reduced hospital admission.

Expert panel consensus recommendations for the pharmacological treatment of acute pain in the Middle East region

The findings of an expert panel convened to review critically how best to apply evidence-based guidelines for the treatment of acute pain in the Middle East region are presented. The panel recommended a three-step treatment protocol. Patients with mild-to-moderate levels of acute pain should be treated with paracetamol (step 1). If analgesia is insufficient after 1-2 days, a selective cyclo-oxygenase-2 inhibitor or, if gastrointestinal safety and bleeding risk are not an issue, a non-specific nonsteroidal anti-inflammatory drug, should be used (step 2). If analgesia remains inadequate, treatment with tramadol, or paracetamol plus codeine/tramadol is recommended (step 3). Patients reporting severe pain should be referred to a pain clinic or specialist for opioid analgesic treatment. Measures of pain and functioning that have been validated in Arabic, with culturally appropriate and easy to understand descriptors, should be used. Early and aggressive acute pain management is important to reduce the risk of pain becoming chronic, especially in the presence of neuropathic features.

Enantiomeric selectivity in behavioural and electrophysiological responses of Aedes aegypti and Culex quinquefasciatus mosquitoes

1-Octen-3-ol is a kairomone for many haematophagous insects including mosquitoes. Numerous studies have examined the effects of racemic 1-octen-3-ol; however, few studies have investigated the role of individual enantiomers in relation to mosquito attraction. In the present study, we investigated the behavioural and electrophysiological responses of two mosquito species, Aedes aegypti and Culex quinquefasciatus, to individual enantiomers and mixtures of 1-octen-3-ol, employing a laboratory Y-tube olfactometer and single sensillum recordings. The olfactory receptor neurons of both Ae. aegypti and Cx. quinquefasciatus had a significantly higher response to the (R)-1-octen-3-ol enantiomer compared to the (S)-1-octen-3-ol enantiomer at 10-9 g μl-1 to 10-6 g μl-1. Behaviourally, Ae. aegypti was more responsive to the (R)-1-octen-3-ol enantiomer, showing an increase in flight activity and relative attraction compared to Cx. quinquefasciatus. The (R)-1-octen-3-ol enantiomer caused an increase in activation for Cx. quinquefasciatus. However, the most notable effect was from an (R:S)-1-octen-3-ol mixture (84:16) that caused significantly more mosquitoes to sustain their flight and reach the capture chambers (demonstrated by a reduced non-sustained flight activity), suggesting that it may have a behaviourally excitatory effect. For Cx. quinquefasciatus, a reduced relative attraction response was also observed for all treatments containing the (R)-1-octen-3-ol enantiomer, either on its own or as part of a mixture, but not with the (S)-1-octen-3-ol enantiomer. This is the first time enantiomeric selectivity has been shown for Ae. aegypti using electrophysiology in vivo. The implications of these results for exploitation in mosquito traps are discussed.

The death-inducing signalling complex is recruited to lipid rafts in Fas-induced apoptosis

Membrane microdomains known as lipid rafts have been shown recently to be involved in Fas signalling and apoptosis in T and B cell lines. Here, we have investigated further the role of lipid rafts in Fas-induced apoptosis in non-transformed human CD4 T cells. We show that Fas-induced apoptosis in CD4 T cells was inhibited by the lipid raft disrupter methyl-beta-cyclodextrin. When lipid rafts were isolated from control and Fas ligand treated cells, we found that a small proportion of Fas was present in the raft fraction in untreated cells and that this was greatly increased upon Fas ligation. The other components of the Death Inducing Signalling Complex (DISC), FADD, and procaspase 8, were also present at higher levels in the raft fraction isolated from Fas ligand treated cells. We conclude that formation of the DISC occurs in lipid rafts and that these membrane microdomains are required for efficient Fas signalling and apoptosis.

Structures of HIV-1 gp120 envelope glycoproteins from laboratory-adapted and primary isolates

BACKGROUND

The gp120 exterior envelope glycoprotein of HIV-1 binds sequentially to CD4 and chemokine receptors on cells to initiate virus entry. During natural infection, gp120 is a primary target of the humoral immune response, and it has evolved to resist antibody-mediated neutralization. We previously reported the structure at 2.5 A of a gp120 core from the HXBc2 laboratory-adapted isolate in complex with a 2 domain fragment of CD4 and the antigen binding fragment of a human antibody. This revealed atomic details of gp120-receptor interactions and suggested multiple mechanisms of immune evasion.

RESULTS

We have now extended the HXBc2 structure in P222, crystals to 2.2 A. The enhanced resolution enabled a more accurate modeling of less-well-ordered regions and provided conclusive identification of the density in the central cavity at the crux of the gp120-CD4 interaction as isopropanol from the crystallization medium. We have also determined the structure of a gp120 core from the primary clinical HIV-1 isolate, YU2, in the same ternary complex but in a C2 crystal lattice. Comparisons of HXBc2 and YU2 showed that while CD4 binding was rigid, portions of the gp120 core were conformationally flexible; overall differences were minor, with sequence changes concentrated on a surface expected to be exposed on the envelope oligomer.

CONCLUSIONS

Despite dramatic antigenic differences between primary and laboratory-adapted HIV-1, the gp120 cores from these isolates are remarkably similar. Taken together with chimeric substitution and sequence analysis, this indicates that neutralization resistance is specified by quaternary interactions involving the major variable loops and thus affords a mechanism for viral adaptation. Conservation of the central cavity suggests the possibility of therapeutic inhibitors. The structures reported here extend in detail and generality our understanding of the biology of the gp120 envelope glycoprotein.

Refractory priapism of unknown etiology in a pediatric patient

Priapism is a urologic emergency that can occur in any age group and every patient should receive prompt urologic consultation. Management of priapism is based on the recognition of underlying pathophysiology; ready differentiation between high-flow and low-flow priapism; reversal of any potential precipitating factors; the use of corporal aspiration irrigation combined with intracavernosal alpha adrenergic therapy; and when necessary, a shunting procedure. Delay in recognition or treatment can be crucial as the incidence of long-term complication rises substantially with the duration of the priapism.

A malignant liver cell tumour in a king snake (Lampropeltis getulus)

A neoplastic lesion in the liver of a king snake, Lampropeltis getulus, was identified as a hepatocellular carcinoma. There were metastases in the spleen.

Intraocular melanoma in the rat

8 cases are reported of intraocular melanoma encountered in treated and untreated rats from 6 chronic toxicity studies.

Ultrastructural study of mesenteric lymph nodes in old rats

The large mononuclear cells showed the features of mononuclear phagocytes and were mainly characterised by a large number of vacuolar structures. The results suggest that there is storage of lipids and mucosubstances, probably in enlarged lysosomes.

Histochemical study of mesenteric lymph nodes in old rats

The main positive reactions in the large mononuclear cell occurring in some nodes were shown with PAS, alcian blue, Sudan black B and acid haematin. The results suggest that in these cells, considered to be mononuclear phagocytes, there is a storage of hexose-containing mucosubstances, acid mucopolysaccharides and choline-containing phospholipids.